The Deganat or Deanery building, of rectangular plan, is attached to the Church of Sant Miquel, and forms the middle section of the Cathedral cloister. It was originally part of the rooms of the chapterhouse for the canons of the Cathedral. By the 13th century it was converted into the seat of the Deanery of Urgellet, a new ecclesiastical administrative unit instituted by the Catalan bishops to replace of the archdeaconry.

In 1822 a group of royalist volunteers opposed to the Trienio Liberal regime, occupied La Seu d’Urgell and constituted the so-called Regency of Urgell or “Regencia Suprema de España”, which replaced the Government of King Ferdinand VII during his captivity. The new Regency established its headquarters in the Deanery building. For this reason, in common parlance, it is said that La Seu d’Urgell was once the capital of Spain.

In 1980, after years of being practically abandoned, the Deanery became home to the extension of the Museu Diocesà d’Urgell.